Safety device for pressure-indicators.



FRANCIS E. COLLIN-SON, 0F LONDON,

ENGLAND, ASSIGNOR OF ONE-HALF TO TAYLOR INSTRUMENT COMPANIES, OFROCHESTER, NEW,YORK, A CORPORATION OF NEW YORK.

SAFETY DEVICE FOR PRESSURE-INDICATORS To all 'whom t may concern:

Be it known that LAFRANCIS E. COLLIN- soN, of London, England, haveinvented certain new and useful Improvements in Safety Devices forPressure-Indicators; and I do hereby] declare the following to bea full,clear, and exact description of the same, reference being had to theaccompanying drawings, forming a part of this specification, and to thereference-numerals marked thereon.

My invention relates to pressure indicators, and more particularly tosuch as are vused in sphygmomanometers and other delicate indicating orrecording instruments, and it has for its object to improve theconstruction of devices of this character so as to obviate fracture ordisarrangement -due to operating under abnormal conditions. Moreparticularly, the invention consists in the provision of means foraffording protection to the flexible or expansible element of thepressure controlled mechanism whereby its movement is limited, so as toprevent its operation beyond a`safe point by an unusual pressure orsuction. To these and other ends the invention consists in certainimprovements and combinations of parts all as will be hereinafter morefully described, the novel features being pointedI out in the claim atthe end of the specification.

The drawing is a sectional view. of an indicator such as used in a usualtype of sphygmomanometer showing it equipped with my presentimprovement.

In the construction shown, A designates a casing including a lowerportion B which is provided with an inlet passage C for conveying thepressure to the working parts anda nipple D adapted to receive aflexible tube or other conductor leading to the source of pressure.Secured within the portion D of the casing is a sleeve E having acentral opening therein, and which supports the eX- pansible or iieXiblemember to be acted upon by the pressure, the expansible member in thepresent instance consisting of a bellows-like structure embodying aseries of metallic diaphragme F which are connected together as shownand are adapted to move toward and away from each other as the presure.falls and rises.

The expansible member is connected to an indicator bysuitable operatingmeans` and in the present arrangement it is provided Specification o1Letters Patent.

. indicator Patented Sept. illl, MM?.

Application fil-ed March 6, 1914. Serial No. 823,018.

with a" central post G secured to the innermost diaphragm F and providedat its upper end -with a socket H, adapted to receive the free end ofthe link I forming a part of the controlling mechanism, which serves torotate the arbor J upon which is mounted the indicating hand K. Theindi- A:cator is arranged for coperation with a scale L as usual in thisclass of devices.

In the operation of instruments of this type, which are usuallyconstructed to act within certain ranges, it frequently happens that theeXpansible member is subjected to an excessive pressure, or an excessivesuction, as for instance when the connecting tube is jerked or suddenlyremoved from the end of the casing and this often results in fracturingthe delicately constructed expansible member, or at least in sostraining its parts as to render itv necessary to correct the device. Toovercome this, I provide a simple means for limiting the movement of theeXpansible member in either direction, and this is preferablyacomplished by forming on the post G an inwardly projecting extension Mwhich is interiorly threaded to receive a valve stem N. The lattercarries a valve 'O which embodies inner and outer yieldable faces P thatcoperate with a pair of valve seats in the passage C so as to cut olfthe pressure supply. The lower face of the sleeve E constitutes one ofthe valve seats with which the valve O coperates, while a threadedsleeve Q is provided,'and may be adjustably arranged within the passageC,

yits inner end coperatingwith the outer face of the valve so as to closethe passage when the valve-stem is moved outwardly, due to a suddensuction. VYThe valve stem N and the sleeve Q are provided with slots Rat the ends thereof to receive a suitable tool by which they can beadjusted.

In the operation of the device, pressure entering through the-passage C,with the parts in the normal positions shown, passes inwardly around-thevalve O, thence around the valve stem N to the interior of the eX-pansible member This causes the post G to move inwardlyand therebyoperate the indicator to show the amount of pressure that is acting. Incase of an unusual or abnormal pressure, when the valve stem is movedinwardly far enough to bring the inner face of the valve O into contactwith the valve seat, the passage is closed and pressure cut olf. Asimilar operation takes place in case of an excessive suction, whichcauses the valve stem to move outwardly and close the passage bybringing the outer face of the valve O into engagement with the innerend of the sleeve Q. The osition of the valve and of the sleeve D can eadjusted to set the instrument for a standard operation and so that itmay operate safely within the determined limits. In case of any tendencyto move the parts of the expansible member i beyond such limits,

it isprevente'd by cutting oi the communicating passage and thusinsuring the protection of the expansible member under all conditions.The device is of simple construction, and can be readily manufacturedand assembled and presents an extremely unique method of accomplishing amuch needed want in this art.

I claim as my invention:

In a sphygmomanometer including a hollow diaphragm connected at one sideto an inlet passage and at its other side to indicating mechanismcontrolled thereby, 'means for preventing breakage of the diaphragm dueto excessive pressure changes consisting of oppoSit-ely disposed valveseats arranged in said inlet passage, avalve movable in oppositedirections between and cooperating with said valve seats, a valve stemcarrying the valve, and a post carried by one side of the diaphragm andhaving an extension projecting through the diaphragm toward the inletopening and forming a support for said valve Stem.

i FRANCIS E. COLLINSON.

lVitnesses:

O. J. WORTH, H. RoNEN.

